302 Vaccinology Flashcards
What was the case of Edward Jenner?
He fed cow pox infected milk from a milk maid to ‘vaccinate’ an orphaned boy
How is Diphteria vaccine created?
Horses are injected with corynebacterium diphteriae toxin
After a few weeks, the antitoxin is prepared for human use
What are the disadvantages of using horse serum for dipheria?
The horse proteins induce anti-antibodies in the patient about a week after use and this can cause secondary immune complex disease
Horse antitoxin is more rapidly eliminated than human antitoxin (horse: 5 days, human:20 days)
Repeat administration can cause severe anaphylactic shock
How can live attenuated vaccines produce an immune responce?
They are only weakened so they can still replicate
Give examples of live attenuated vaccine
BCG, shingles, MMR, nasal spray influenza, rubeola
Give examples of inactivated vaccines
Influenza, pertussis, poliomyelitis, typhoid
What is pertussis?
Whooping cough
Symptoms:
Runny or stuffed-up nose
Low-grade fever
Mild, occasional cough (babies do not do this)
Apnea and cyanosis in babies and young children
What is poliomyelitis?
Polio
Symptoms:
It can infect the CNS and cause paralysis
Fever
Fatigue
Vomiting
Stiffness of neck and limbs
What is typhoid?
A bacterial infection that can spread throughout the body, affecting many organs
Can cause complications and death is not treated quickly with antibiotics
Give examples of recombinant and synthetic vaccines
Subunit vaccine (proteins)
Polysaccharide and conjugate
Toxoid
Virus-like article
DNA/RNA
Give examples of subunit vaccines (protein)
Hepatitis B, TB (experimental stage)
Give examples of virus-like particle (VLP) vaccines
HPV
Give examples of subunit/conjugate vaccines
HIB (polysaccharide plus protein)
What is HIB?
Haemophilus influenzae type b
Symptoms:
Fever and chills
Excessive tiredness
Pain in the belly
Nausea with or without vomiting
Diarrhea
Anxiety
Shortness of breath or difficulty breathing
(confusion)
Give examples of toxoid vaccines
Tetanus, Diphteria
Give examples of DNA/RNA vaccines
SARS-CoV-2
Cancer
What are some additional ingredients in vaccines?
Liquids
Buffers
stabilisers
Adjuvants
What are adjuvants?
Substances that increase the immune response
They attract immune cells to the site of infection
What are some common passive vaccinations in practice?
-Hepatitis B hyperimmune serum (post exposure)
-Tetanus hyperimmune serum (post exposure)
-Rabies hyperimmune serum (post exposure)
-Anti-venoms, anti-toxins etc (post exposure)
-Hepatitis A hyperimmune serum as prophylaxis
-VZV hyperimmune globulin prophylaxis given for babies born to mothers who develop varicella in a 1 week period before or after delivery
How is intracellular mRNA stability achieved?
A modified nucleotide positioned at 5’ end (cap)
A poly (A) tail adds length
The composition and structure if the 3’ untranslated reGions (3’UTR)
What are some advantages of RNA vaccines?
No pathogen particles or inactivated pathogen
Non-infectious
Not integrated into host genome (RNA strand is degraded after protein is made)
Reliable immune response
Few side effects
Well tolerated by healthy individuals
Can be produced rapidly
Can be used for effective cancer vaccines
What % of population needs to vaccine to achieve herd immunity of Diphtheria?
85%
What % of population needs to vaccine to achieve herd immunity of Measles?
83-94%
What % of population needs to vaccine to achieve herd immunity of Mumps?
75-86%
What % of population needs to vaccine to achieve herd immunity of Pertussis?
92-94%
What % of population needs to vaccine to achieve herd immunity of Polio?
80-86%
What % of population needs to vaccine to achieve herd immunity of Rubella?
83-85%
What % of population needs to vaccine to achieve herd immunity of COVID-19?
60-70%
What happens in the body during primary infection?
Recruitment of B-cells producing antibodies and T-cells over 2 weeks
IgM peak: 8-10 days
IgG peak: 21 days
T-cell peak: 12-15 days
What is the difference between T and B-cells?
T cells are responsible for cell-mediated immunity which begins when a pathogen is engulfed by an antigen-presenting cell, in this case, a macrophage
B cells, which mature in the bone marrow, are responsible for antibody-mediated immunity
What happens in the body during a secondary infection?
Quick response
IgG and T-cells peak within 5-10 days or quicker
There may be no symptoms
What is the original antigenic sin?
the phenomenon in which immunity against pathogens or antigens is shaped by the host’s first exposure to a related pathogen or antigen
Repeated infection causes an existing, ineffective immune response is pushed but no new immune response is made
It lead to severe disease
What is narcolepsy?
A chronic neurological disorder that affects the brain’s ability to control sleep-wake cycles
What is cataplexy?
Complete loss of muscle control
Which vaccine caused narcolepsy?
Swine flu vaccine
It was attributed to the use of AS03 adjuvant
Name some adjuvants used in vaccines?
Mineral salts Eg. aluminium hydroxide
Micro-fluidised detergents, emulsions, saponins Eg. MF59, AS03
Toll-like receptor agonists Eg. CpG, flagellin
What are saponins?
Saponins are naturally occurring compounds that are widely distributed in all cells of legume plants
They derive their name from their ability to form stable, soap-like foams in aqueous solutions
